The rising cost of vitamin D testing in Australia: time to establish guidelines for testing

Consensus Statement on Vitamin D Status Assessment and Supplementation: Whys, Whens, and Hows

The 6th International Conference, "Controversies in Vitamin D," was convened to discuss controversial topics, such as vitamin D metabolism, assessment, actions, and supplementation. Novel insights into vitamin D mechanisms of action suggest links with conditions that do not depend only on reduced solar exposure or diet intake and that can be detected with distinctive noncanonical vitamin D metabolites. Optimal 25-hydroxyvitamin D (25(OH)D) levels remain debated. Varying recommendations from different societies arise from evaluating different clinical or public health approaches. The lack of assay standardization also poses challenges in interpreting data from available studies, hindering rational data pooling and meta-analyses. Beyond the well-known skeletal features, interest in vitamin D's extraskeletal effects has led to clinical trials on cancer, cardiovascular risk, respiratory effects, autoimmune diseases, diabetes, and mortality. The initial negative results are likely due to enrollment of vitamin D-replete individuals. Subsequent post hoc analyses have suggested, nevertheless, potential benefits in reducing cancer incidence, autoimmune diseases, cardiovascular events, and diabetes. Oral administration of vitamin D is the preferred route. Parenteral administration is reserved for specific clinical situations. Cholecalciferol is favored due to safety and minimal monitoring requirements. Calcifediol may be used in certain conditions, while calcitriol should be limited to specific disorders in which the active metabolite is not readily produced in vivo. Further studies are needed to investigate vitamin D effects in relation to the different recommended 25(OH)D levels and the efficacy of the different supplementary formulations in achieving biochemical and clinical outcomes within the multifaced skeletal and extraskeletal potential effects of vitamin D.

Comparative Performance Assessment of Novel Fluorescence Immunoassay POCTs for Measuring Circulating Levels of Vitamin-D

Vitamin D (Vit D) is a fat-soluble molecule acting like a hormone, and it is involved in several biological mechanisms such as gene expression, calcium homeostasis, bone metabolism, immune modulation, viral protection, and neuromuscular functions. Vit D deficiency can lead to chronic hypocalcemia, hyperparathyroidism, and many other pathological conditions; in this context, low and very low levels of 25-hydroxy-vitamin D (25-OH-D) were found to be associated with an increased risk of COVID-19 infection and the likelihood of many severe diseases. For all these reasons, it is important to quantify and monitor 25-OH-D levels to ensure that the serum/blood concentrations are not clinically suboptimal. Serum concentration of 25-OH-D is currently the main indicator of Vit D status, and it is currently performed by different assays, but the most common quantitation techniques involve immunometric methods or chromatography. Nevertheless, other quantitation techniques and instruments are now emerging, such as AFIAS-1® and AFIAS-10® (Boditech and Menarini) based on the immunofluorescence analyzer, that guarantee an automated system with cartridges able to give quick and reliable results as a point-of-care test (POCT). This work aims to compare AFIAS-1® and AFIAS-10® (Boditech and Menarini) Vit D quantitation with Ultra High-Performance Liquid Chromatography coupled with tandem mass spectrometry that currently represents the gold standard technique for Vit D quantitation. The analyses were performed in parallel on 56 samples and in different conditions (from fresh and frozen plasma) to assess the reliability of the results. Any statistically significant differences in methods, the fixed error, and the error proportional to concentration were reported. Results obtained in all conditions showed a good correlation between both AFIAS® instruments and LC-MS/MS, and we can affirm that AFIAS-1® and AFIAS-10® are reliable instruments for measuring 25-OH-D with accuracy and in a fast manner.

Vitamin D testing: Impact of changes to testing guidelines on detection of patients at risk of vitamin D deficiency

BACKGROUND

Changes were made to the Australian guidelines for vitamin D testing in November 2014 which restricted the patients who could be tested and reimbursed under the Medical Benefits Schedule. A retrospective study was conducted to assess the impact of the changes.

METHODS

Data from 588,021 cases tested for vitamin D over the period of 2014 to 2017 were obtained and the results in 149,808 cases tested before the change in guidelines were compared to 438,213 cases tested afterwards.

RESULTS

The results showed an initial fall in requests took place after the introduction of changes, but request numbers had returned to pre-change levels by November 2016. Furthermore, following the intervention, there was a significant reduction in the number of cases of vitamin D deficiency (<50 nmol/L) detected after November 2014 (P < 0.001) with odds ratio (OR) calculations showing the strongest effect for the sub-cohort of 0-20 nmol/L (OR = 1.77). For patient vitamin D levels >71 nmol/L, the pattern of detection inverted with more cases of sufficiency being detected after the intervention than before (OR from 0.84 to 0.48, P <0.001).

CONCLUSIONS

The failure to show a sustained reduction in vitamin D testing is a common finding with demand management strategies to limit test requesting. More significant is the failure of the intervention to improve the detection of vitamin D deficiency. These failures highlight the need for better tools to manage test requesting including the use of audit and outcomes measurement to guide future interventions.

Prediction models and questionnaires developed to predict vitamin D status in adults: a systematic review

A systematic review of prediction models/questionnaires developed to identify people with deficient/insufficient vitamin D status shows the potential of self-reported information to estimate vitamin D status. The objective is to identify and compare existing screening tools, developed to identify vitamin D deficiency or insufficiency in adults. A systematic search of literature was conducted using MEDLINE, Scopus, Web of Science and CINAHL databases. Risk of bias and applicability concerns were assessed by quality assessment of diagnostic accuracy studies (QUADAS-2). Data were extracted on socio-demographic, anthropometric, risk factors, serum 25 hydroxyvitamin D [25(OH)D] levels, statistical methods and predictive ability. A total of 12 studies were considered for inclusion for this systematic review after screening of 4851 abstracts and 15 full-text articles. Ten of twelve studies developed prediction models and 2 studies developed questionnaires. The majority of studies had low risk of bias and applicability as assessed by QUADAS-2. All studies included only self-reported predictors of vitamin D status in their final models and development of scores. Sunlight exposure and related factors were important significant contributors to the predictive ability of the models and/or questionnaires. Sensitivity and specificity of the prediction models or questionnaires ranged from 55 to 91% and 35 to 84%, respectively. Six out of twelve studies converted final models to scores associated with vitamin D status. There was no evidence that any of these existing tools have been translated into clinical practice. The prediction models or questionnaires identified in this systematic review were moderately sensitive and specific for identifying people with vitamin D deficiency or insufficiency. The substantial contribution of sunlight exposure to the prediction of vitamin D status highlights the importance of including this information when developing vitamin D screening tools.

Potentially inappropriate testing for vitamin D deficiency: a cross-sectional study in Switzerland

Background

There is consensus that vitamin D supplementation is often indicated but population-based screening by laboratory testing for vitamin D deficiency is inadequate. Testing should be restricted to people at high risk of severe deficiency. This study describes the current lab testing for vitamin D deficiency in the adult population of Switzerland.

Methods

We assessed Swiss health insurance data (SWICA) for incidence of lab testing for vitamin D levels, comparing the years 2015 and 2018. Claims were analyzed for associations between lab testing and age, sex, medical indications, insurance status and geographic location in multivariable regression analyses. We also estimated the costs of vitamin D testing.

Results

Data from 200,043 and 200,046 persons for 2015 and 2018, respectively, were analyzed. Vitamin D level was tested in 14% of the sample population in 2015 and 20% in 2018. Testing increased by 69% for individuals aged 26–30. Testing was associated with being middle-aged to young senior citizens, female, medical indications (pregnancy, renal disease, osteoporosis, hyperparathyroidism, HIV, glucocorticoid intake), more chronic conditions, having a mandatory insurance with a low deductible, additional insurance coverage, and living in urban areas. We estimate that the total laboratory cost to mandatory insurance was about 90 million Swiss francs in 2018.

Conclusions

Despite recommendations for routine vitamin D supplementation, vitamin D testing of low risk individuals is common and increasing in Switzerland.

A prediction tool for vitamin D deficiency in New Zealand adults

PURPOSE

This study aims to develop a model for predicting vitamin D deficiency in New Zealand adults using easily accessible clinical characteristics.

METHODS

Data were derived from the Vitamin D Assessment (ViDA) study dataset. Included participants in the main analysis were aged 50-84 years and resided in Auckland, New Zealand. The dataset was split into a discovery dataset in which the prediction model was developed (n = 2036) and a validation dataset in which it was tested (n = 2037). The prediction model was developed using clinical characteristics in a logistic regression analysis with deseasonalised serum 25OHD (DS-25OHD) as the dependent variable.

RESULTS

DS-25OHD < 40 nmol/L was found in 8.2% of European participants, 18.8% of Māori participants, 23.1% of Pacific participants and 52.2% of South Asian participants. Predictors for DS-25OHD < 40 nmol/L in the European sub-cohort included increasing age, female sex, higher body mass index, current smoking, no alcohol intake, lower self-reported general health status, lower physical activity hours, lower outdoor hours and no use of vitamin D-containing supplementation. The area under the curve in the discovery dataset was 0.73, and in the validation dataset was 0.71. Of those with a prediction score ≥ 10 (total risk score range 0-21.5), the sensitivity and specificity for predicting vitamin D deficiency was 0.90 and 0.41, respectively.

CONCLUSION

Non-European ethnicity is an important risk factor for vitamin D deficiency. Our vitamin D deficiency prediction model performed well and demonstrates its potential as a tool that can be integrated into clinical practice for the prediction of vitamin D deficiency.

The Vitamin D in Pregnancy Study: a prospective prebirth cohort in southern Australia

PURPOSE

The Vitamin D in Pregnancy Study is a long-term ongoing cohort study. It was conceived to explore relationships between maternal vitamin D status in pregnancy and offspring growth and development, and has since diversified to include a wide range of physical and mental health exposures and outcomes.

PARTICIPANTS

Recruitment was from the University Hospital Geelong (Barwon Health) antenatal clinic, Geelong, Victoria, Australia, between 2002 and 2004. 475 women were initially recruited, which resulted in 400 eligible mother-child pairs at birth.

FINDINGS TO DATE

The cohort has been followed up twice in pregnancy, at birth, and 1 year, 6 years and 11 years post birth. The study has reported an association between vitamin D in pregnancy and musculoskeletal health and body composition in the children.

FUTURE PLANS

Subject to funding, there will be a prospective young adult follow-up. This profile aims to foster both cross-national and international collaborations with both existing and future data collection.

The Pursuit of Value in Laboratory Medicine - Progress and Challenges

The pressure on healthcare budgets including laboratory medicine is relentless and the focus on activities and costs remains the dominant funding model of laboratory medicine everywhere. The limitations of this model are well documented and for a decade or more laboratory professions worldwide have started looking at alternative models where the value of laboratory medicine and its impact on patient outcomes are the predominant driving force. There are multiple ways to determine the value of a medical test, particularly if one takes into consideration its impact upon the complete clinical pathway. Thus various approaches to value determination are being explored by a number of international organisations. These organisations will be reviewed below, including one which uses the concept of a value proposition that describes in detail how a test should be implemented by measuring its clinical, operational and economic impact. All approaches for determination of value require professional leadership. There is a need for research of varying types including that related to translating global evidence into local practice, a key challenge facing laboratory medicine and healthcare generally. Another challenge is to think and act beyond the silo of the laboratory to achieve greater collaboration with those colleagues more directly involved in patient care.

Vitamin D prescribing in children in UK primary care practices: a population-based cohort study

OBJECTIVE

To examine temporal changes in the incidence and patterns of vitamin D supplementation prescribing by general practitioners (GPs) between 2008 and 2016.

DESIGN

Population-based cohort study.

SETTING

UK general practice health records from The Health Improvement Network.

PARTICIPANTS

Children aged 0 to 17 years who were registered with their general practices for at least 3 months.

OUTCOME MEASURES

Annual incidence rates of vitamin D prescriptions were calculated, and rate ratios were estimated using multivariable Poisson regression to explore differences by sociodemographic factors. Data on the type of supplementation, dose, dosing schedule, linked 25-hydroxyvitamin D (25(OH)D) laboratory test results and clinical symptoms suggestive of vitamin D deficiency were analysed.

RESULTS

Among 2 million children, the crude annual incidence of vitamin D prescribing increased by 26-fold between 2008 and 2016 rising from 10.8 (95% CI: 8.9 to 13.1) to 276.8 (95% CI: 264.3 to 289.9) per 100 000 person-years. Older children, non-white ethnicity and general practices in England (compared with Wales/Scotland/Northern Ireland) were independently associated with higher rates of prescribing. Analyses of incident prescriptions showed inconsistent supplementation regimens with an absence of pre-supplementation 25(OH)D concentrations in 28.7% to 56.4% of prescriptions annually. There was an increasing trend in prescribing at pharmacological doses irrespective of 25(OH)D concentrations, deviating in part from UK recommendations. Prescribing at pharmacological doses for children with deficient status increased from 3.8% to 79.4%, but the rise was also observed in children for whom guidelines recommended prevention doses (0% to 53%). Vitamin D supplementation at pharmacological doses was also prescribed in at least 40% of children with no pre-supplementation 25(OH)D concentrations annually.

CONCLUSIONS

There has been a marked and sustained increase in vitamin D supplementation prescribing in children in UK primary care. Our data suggests that national guidelines on vitamin D supplementation for children are not consistently followed by GPs.

Factors Associated with Vitamin D Testing, Deficiency, Intake, and Supplementation in Patients with Chronic Pain

Vitamin D deficiency is a public health issue, with reports of six- to twenty-five-fold rise in vitamin D testing. Vitamin D deficiency has been linked to many chronic diseases such as diabetes mellitus, cardiovascular disease, depression, and chronic pain. Identifying factors associated with risk of deficiency in individuals with chronic pain will help minimize time and cost. This study aims to examine the factors associated with vitamin D testing, intake, and physician-advised supplementation in individuals with chronic pain. Using a cross-sectional design, data were collected from 465 individuals with chronic pain. These data were analyzed using penalized logistic regression with the LASSO technique. Fifty-seven percent reported being tested for vitamin D, about 40% reported being diagnosed with vitamin D deficiency, and of those who had been tested, 60% reported taking vitamin D supplementation. The findings suggest older age (OR 3.12, CI [1.02, 9.50]) and higher mean pain intensity score (OR 2.02, CI [1.13, 3.59]) increased an individual's chance of being vitamin D deficient. Unemployment or on leave due to pain (OR 1.79, [CI 1.03, 3.11]), part-time employment (OR 1.86, CI [1.02, 3.39]), and being a resident of Australia (OR 2.32, CI [1.13, 4.72]) increased chances of being tested for vitamin D. Being diagnosed with vitamin D deficiency (OR 6.67, CI [2.75, 16.19]), unemployed or on leave due to pain (OR 3.71, CI [1.25, 11.00]), and in part-time employment (OR 2.69, CI [0.86, 8.38]) were associated with physician-advised vitamin D supplementation. Our results may have practical implications, as identifying pretest risk factors may assist in identifying who is at risk of vitamin D deficiency, whom to test, and when to treat.

Can oral vitamin D prevent the cardiovascular diseases among migrants in Australia? Provider perspective using Markov modelling

The study was designed to model the effectiveness and cost effectiveness of oral Vitamin D supplementation as a primary prevention strategy for cardiovascular disease among a migrant population in Australia. It was carried out in the Community Health Service, Kensington, Melbourne. Best-case scenario analysis using a Markov model was employed to look at the health care providers' perspective. Adult migrants who were vitamin D deficient and free from cardiovascular disease visiting the medical centre at least once during the period from 1 January 2010 to 31 December 2012 were included in the study. The blood pressure-lowering effect of vitamin D was taken from a published meta-analysis and applied in the Framingham 10 year cardiovascular risk algorithm (with and without oral vitamin D supplements) to generate the probabilities of cardiovascular events. A Markov decision model was used to estimate the provider costs associated with the events and treatments. Uncertainties were derived by Monte Carlo simulation. Vitamin D oral supplementation (1000 IU/day) for 10 years could potentially prevent 31 (interquartile range (IQR) 26 to 37) non-fatal and 11 (IQR 10 to 15) fatal cardiovascular events in a migrant population of 10,000 assuming 100% compliance. The provider perspective incremental cost effectiveness per year of life saved was AU$3,992 (IQR 583 to 8558). This study suggests subsidised supplementation of oral vitamin D may be a cost effective intervention to reduce non-fatal and fatal cardiovascular outcomes in high-risk migrant populations.

Self-Reported Changes in Sun-Protection Behaviors at Different Latitudes in Australia

Sun exposure is the most important source of vitamin D, but is also a risk factor for skin cancer. This study investigated attitudes toward vitamin D, and changes in sun-exposure behavior due to concern about adequate vitamin D. Participants (n = 1002) were recruited from four regions of Australia and completed self- and interviewer-administered surveys. Chi-square tests were used to assess associations between participants' latitude of residence, vitamin D-related attitudes and changes in sun-exposure behaviors during the last summer. Multivariate logistic regression analyses were used to model the association between attitudes and behaviors. Overall, people who worried about their vitamin D status were more likely to have altered sun protection and spent more time in the sun people not concerned about vitamin D. Concern about vitamin D was also more common with increasing latitude. Use of novel item response theory analysis highlighted the potential impact of self-reported behavior change on skin cancer predisposition due concern to vitamin. This cross-sectional study shows that the strongest determinants of self-reported sun-protection behavior changes due to concerns about vitamin D were attitudes and location, with people at higher latitudes worrying more.

Test ordering in an evidence free zone: Rates and associations of Australian general practice trainees' vitamin D test ordering

RATIONALE, AIMS AND OBJECTIVES

Indiscriminate health screening is increasingly seen as being problematic. In particular, vitamin D testing rates are increasing rapidly despite recommendations against population screening. The purpose of this study was to determine the level of vitamin D testing among family practice/general practitioner (GP) trainees and to establish associations of this testing.

METHODS

Cross-sectional analysis of data from the ReCEnT (Registrars Clinical Encounters in Training) cohort study. The setting was GP practices in four Australian states. Data from 60 consecutive consultations per trainee were recorded each 6-month training term (up to four terms).

RESULTS

Vitamin D tests were ordered in 726 (1.0%) of encounters (n = 69 412). Vitamin D test ordering was significantly associated with patients being older, female and non-English speaking. Trainees were more likely to test if they worked in a completely bulk-billing practice (i.e. a practice without any patient payment), if more problems were dealt with, more pathology tests were ordered in the consultation and if a lipid profile was ordered. They were less likely to test if they sought in-consultation advice or information. The most common reasons for testing were 'check-up' and 'health maintenance'.

CONCLUSIONS

In this first report of associations of vitamin D testing in the GP setting, we found that non-targeted vitamin D testing (testing inconsistent with current guidelines) is widespread in GP trainees' practice. Adoption of more rational testing approaches is needed.

Maternal vitamin D supplementation during pregnancy prevents vitamin D deficiency in the newborn: an open-label randomized controlled trial

OBJECTIVE

To determine whether maternal vitamin D supplementation, in the vitamin D deficient mother, prevents neonatal vitamin D deficiency.

DESIGN

Open-label randomized controlled trial.

SETTING

Metropolitan Melbourne, Australia, tertiary hospital routine antenatal outpatient clinic.

PARTICIPANTS

Seventy-eight women with singleton pregnancies with vitamin D deficiency/insufficiency (serum 25-OH Vit D < 75 nmol/l) at their first antenatal appointment at 12-16-week gestation were recruited.

INTERVENTION

Participants were randomized to vitamin D supplementation (2000-4000 IU cholecalciferol) orally daily until delivery or no supplementation.

MAIN OUTCOME MEASURES

The primary outcome was neonatal serum 25-OH vit D concentration at delivery. The secondary outcome was maternal serum 25-OH vit D concentration at delivery.

RESULTS

Baseline mean maternal serum 25-OH vit D concentrations were similar (P = 0·9) between treatment (32 nmol/l, 95% confidence interval 26-39 nmol/l) and control groups (33 nmol/l, 95% CI 26-39 nmol/l). Umbilical cord serum 25-OH vit D concentrations at delivery were higher (P < 0·0001) in neonates of treatment group mothers (81 nmol/l, 95% CI; 70-91 nmol/l) compared with neonates of control group mothers (42 nmol/l, 95% CI; 34-50 nmol/l) with a strongly positive correlation between maternal serum 25-OH Vit D and umbilical cord serum 25-OH vit D concentrations at delivery (Spearman rank correlation coefficient 0·88; P < 0·0001). Mean maternal serum 25-OH Vit D concentrations at delivery were higher (P < 0·0001) in the treatment group (71 nmol/l, 95% CI; 62-81 nmol/l) compared with the control group (36 nmol/l, 95% CI; 29-42 nmol/l).

CONCLUSION

Vitamin D supplementation of vitamin D deficient pregnant women prevents neonatal vitamin D deficiency.

Vitamin D testing patterns among general practitioners in a major Victorian primary health care service

OBJECTIVE

To examine 25(OH)D testing patterns and frequency among general practitioners in a major community health service.

METHOD

A clinical audit of patient records at a community health centre in Melbourne was undertaken. Patients aged 18 years and above were included. Univariate and multivariate logistic regression was used to examine the association between vitamin D testing and socio-demographic characteristics while Poisson regression was used for the frequency of testing.

RESULTS

There were 1,217 patients tested for serum 25(OH)D. The community health centre was served by 12 general practitioners and an infectious disease specialist. The odds of vitamin D testing showed a positive, albeit weak, association with age (OR 1.01, 95%CI 1.00-1.02, p<0.05), were higher among females than males (OR 1.42, 95%CI 1.18-1.70, p<0.05) and higher among migrants compared to non-migrants (OR 2.57, 95%CI 2.14-3.09, p<0.05). The frequency of testing was also higher among females than males (IRR 1.17, 95%CI 1.07-1.28, p<0.05) and higher among migrants than non-migrants (IRR 1.19, 95%CI 1.08-1.31, p<0.05).

CONCLUSION

Advancing age, being female and being a migrant were associated with an increased likelihood of vitamin D testing.

IMPLICATIONS

Development of evidence-based policies and guidelines are needed to manage over-testing of vitamin D in Australia. Studies that include health services from different areas are required to understand vitamin D testing patterns among the general practitioners.

Tightrope Walking: Using Predictors of 25(OH)D Concentration Based on Multivariable Linear Regression to Infer Associations with Health Risks

The debate on the causal association between vitamin D status, measured as serum concentration of 25-hydroxyvitamin D (25[OH]D), and various health outcomes warrants investigation in large-scale health surveys. Measuring the 25(OH)D concentration for each participant is not always feasible, because of the logistics of blood collection and the costs of vitamin D testing. To address this problem, past research has used predicted 25(OH)D concentration, based on multivariable linear regression, as a proxy for unmeasured vitamin D status. We restate this approach in a mathematical framework, to deduce its possible pitfalls. Monte Carlo simulation and real data from the National Health and Nutrition Examination Survey 2005-06 are used to confirm the deductions. The results indicate that variables that are used in the prediction model (for 25[OH]D concentration) but not in the model for the health outcome (called instrumental variables), play an essential role in the identification of an effect. Such variables should be unrelated to the health outcome other than through vitamin D; otherwise the estimate of interest will be biased. The approach of predicted 25(OH)D concentration derived from multivariable linear regression may be valid. However, careful verification that the instrumental variables are unrelated to the health outcome is required.

Assessment of vitamin D and its association with cardiovascular disease risk factors in an adult migrant population: an audit of patient records at a Community Health Centre in Kensington, Melbourne, Australia

Background

Vitamin D deficiency is a global public health problem associated with increased risk of cardio-metabolic diseases and osteoarthritis. Migrants with dark skin settled in temperate climates are at greater risk of both vitamin D deficiency and cardiovascular diseases. This study aims to identify the risk of vitamin D deficiency and associations with cardiovascular disease in a migrant population in Australia.

Methods

An audit was carried out at a Community Health Service in Kensington, Melbourne which, services a large migrant population. Data from the clinical records of all adults who visited the medical centre at least once during the period from 1^st January 2010 to 31^st December 2012 was extracted. The future (10 year) coronary heart disease risk was estimated using Framingham Risk Score.

Results

The centre has given higher priority to vitamin D testing in migrants, those middle-aged, females and those with diabetes and osteoarthritis. Migrants from countries located in lower latitude regions (Latitude N23⁰ to S23⁰) were 1.48 (95% C.I. 1.32-1.65) times more likely to develop vitamin D deficiency post migration and 0.44 (95% C.I. 0.31-0.62) times less likely to have a >15% 10-year risk of coronary heart disease when compared to their Australian-born counterparts.

Conclusions

Adherence to a high risk strategy for vitamin D testing was observed in the centre. Pre-migration latitude is an important factor for vitamin D deficiency (lower the latitude higher the risk) and in predicting future risk of cardiovascular disease in migrants. These findings suggest that a targeted approach for vitamin D testing, including zone of origin might better identify individuals at higher risk of both vitamin D deficiency and cardiovascular disease.

Measurements of 25-hydroxyvitamin D concentrations in archived dried blood spots are reliable and accurately reflect those in plasma

CONTEXT

Recognition that vitamin D might be associated with many chronic diseases has led to large-scale epidemiological and clinical studies. Dried blood spots (DBS) are a useful resource for these studies. Consequently, accurate, efficient, and inexpensive assays to quantify 25-hydroxyvitamin D (25OHD) in DBS are required.

OBJECTIVE

This study evaluated the validity and reliability of a liquid chromatography-tandem mass spectrometry assay for measuring 25OHD in archived DBS and compared measurements of 25OHD in DBS with those in plasma.

DESIGN AND PARTICIPANTS

Sixty-two participants in the Melbourne Collaborative Cohort Study who had plasma and matching DBS stored since study entry in the early 1990s were randomly selected for a study calibrating 25OHD concentrations in DBS with plasma. As part of a study of vitamin D and mortality, cancer, and diabetes, we also assessed the reliability of measurements from DBS using 500 replicates placed randomly within 31 batches run over 15 months.

OUTCOME MEASURE

25OHD concentrations were measured by liquid chromatography-tandem mass spectrometry.

RESULTS

There was good agreement between measurements of 25OHD from DBS and plasma; R(2) = 0.73 from a regression of plasma concentration on DBS concentration. The within-batch and between-batch intraclass correlations from the 500 replicate measurements were 0.82 (95% confidence interval, 0.80, 0.85) and 0.73 (95% confidence interval, 0.68, 0.78), respectively.

CONCLUSIONS

Measuring 25OHD in DBS is a valid and reliable alternative to measuring 25OHD in sera or plasma. A simple calibration model was developed to convert measurements from DBS to equivalent plasma measurements, thus enabling comparisons against clinical reference ranges and with studies using sera or plasma samples.

Insignificant medium-term vitamin D status change after 25-hydroxyvitamin D testing in a large managed care population

Objectives

To examine the clinical utility of 25-hydroxyvitamin D (25(OH)D) testing in achieving medium-term vitamin D (VD) sufficiency in a managed care population.

Methods

Retrospective study of a continuously-enrolled patient population in a 3-year period between 2011 and 2013. Primary outcome was VD status at ∼1 year after 25(OH)D testing. Patient demographics, comorbidities, medications, and 25(OH)D test results were gathered from relevant databases and multivariate logistic regression analysis used to study the risk factors of persistent VD deficiency or insufficiency.

Results

Of 22,784 patients, 7533 (females 69.3%) did 14,563 25(OH)D tests, with an estimated cost of $582,520. Of the 7533 patients, 1126 had another 25(OH)D test at 300–400 days after the first one. Based on the two test results, 234 patients (20.8%) maintained sufficient 25(OH)D levels; 132 (11.7%) turned from VD-sufficient into VD-insufficient or -deficient; 538 (47.8%) remained VD-insufficient or -deficient, and only 222 (19.7%) improved to be VD-sufficient. Overall, only 8.0% more patients were VD-sufficient at ∼1 year after 25(OH)D testing. Only younger age and higher BMI were independent risk factors for persistent low 25(OH)D levels and high-dose VD use was not associated with achieving VD sufficiency.

Conclusions

25(OH)D testing only benefits a small portion of patients thus lacks clinical utility in achieving VD sufficiency in the medium term but incurs a significant cost. A practical strategy to treat VD deficiency or insufficiency is needed; without it, 25(OH)D testing adds little value to most patients’ health and should be used with discretion.

Vitamin d supplementation in australia: implications for the development of supplementation guidelines

High rates of vitamin D deficiency and testing have been reported in Australia, yet there are few reports regarding vitamin D supplement use. Australian wholesale sales data was obtained for vitamin D supplements for the period 2000-2011. There has been a threefold increase in supplement sales over the past decade, whereby over A$94 million supplements containing vitamin D in Australia were sold during the year 2010. There were eighty-nine manufacturers that produce a variety of 195 vitamin D products. The amount of vitamin D in these products varies considerably, from 40 to 1000 IU per unit, although supplements containing only vitamin D had the highest amount of vitamin D. There was a trend for sales to increase in winter months. Given the potential public health benefits of vitamin D, there is an urgent need for a better understanding of supplementation use and for the development of supplementation.

Ten clinician-driven strategies for maximising value of Australian health care

OBJECTIVE

To articulate the concept of high-value care (i.e. clinically relevant, patient-important benefit at lowest possible cost) and suggest strategies by which clinicians can promote such care in rendering the Australian healthcare system more affordable and sustainable.

METHODS

Strategies were developed by the author based on personal experience in clinical practice, evidence-based medicine and quality improvement. Relevant literature was reviewed in retrieving studies supporting each strategy.

RESULTS

Ten strategies were developed: (1) minimise errors in diagnosis; (2) discontinue low- or no-value practices that provide little benefit or cause harm; (3) defer the use of unproven interventions; (4) select care options according to comparative cost-effectiveness; (5) target clinical interventions to those who derive greatest benefit; (6) adopt a more conservative approach nearing the end of life; (7) actively involve patients in shared decision making and self-management; (8) minimise day-to-day operational waste; (9) convert healthcare institutions into rapidly learning organisations; and (10) advocate for integrated patient care across all clinical settings.

CONCLUSIONS

Clinicians and their professional organisations, in partnership with managers, can implement strategies capable of maximising value and sustainability of health care in Australia. What is known about this topic? Value-based care has emerged as a unitary concept that integrates quality and cost, and is being increasingly used to inform healthcare policy making and reform. What does this paper add? There is scant literature that translates the concept of high value care into actionable enhancement strategies for clinicians in everyday practice settings. This article provides 10 strategies with supporting studies in an attempt to fill this gap. What are the implications for practitioners? If all practitioners, in partnership with healthcare managers, attempted to enact all 10 strategies in their workplaces, a significant quantum of healthcare resources could be redirected from low- to high-value care, culminating in much greater health benefit from the healthcare dollars currently being spent. However, such reforms will require a shift in clinician thinking and practice away from volume-based care to value-based care.

The prevalence of vitamin D deficiency in children in the Northern Territory

AIMS

The primary aim of this study was to determine the frequency of vitD deficiency/insufficiency in an opportunistic sample of Northern Territory (NT) children. The secondary aim was to evaluate whether: (i) 25(OH)vitD (25(OH)D) levels differ between Indigenous/non-Indigenous children; and (ii) VitD insufficiency is associated with increased acute/infective hospitalisations.

METHODS

Twenty-five (OH)D levels were measured in 98 children <16 years between August 2011 and January 2012 (children hospitalised acutely/non-acutely and well children from other studies based in Darwin). VitD deficiency was defined as 25(OH)D < 50 nmol/L, and insufficiency was postulated to be <75 nmol/L. Demographic data were collected, and computer records were reviewed.

RESULTS

Median age was 59 months (range 2-161); 3.1% were vitD deficient, 19.4% insufficient. There was no significant difference in mean 25(OH)D level between Indigenous (93.2, standard deviation (SD) 21.9, n = 42) and non-Indigenous (97.3, SD 27.9, n = 56) children (P = 0.32). Median number of hospitalisations/year were similar (P = 0.319) between vitD sufficient (0.34, range 0-12, n = 76) and insufficient (0.22, 0-6, n = 22) children. There was no significant difference between number of infective admissions per year between vitD sufficient/insufficient groups (P = 0.119).

CONCLUSIONS

Compared with US data (19% deficient, 65% insufficient) fewer NT children are vitD deficient/insufficient. In our limited sample, being vitD insufficient was not associated with increased acute/infective hospitalisations, but a larger unbiased sample of NT children is needed. More information is needed about the optimum level of vitD for non-bone-related health in children.

The Vitamin D paradox: bone density testing in females aged 45 to 74 did not increase over a ten-year period despite a marked increase in testing for vitamin D

AIM

To determine whether increased vitamin D testing resulted in improved osteoporosis detection in Australian females aged 45-74 yr.

METHODS

Longitudinal analysis of bone densitometry, 25-hydroxyvitamin D (25(OH)D) and full blood count (FBC) testing between 2001 and 2011. The number and rate of tests per 100,000 individuals and benefit in dollars for bone densitometry, 25(OH)D and FBC from 2001-2011 for individuals aged 45-74 yr were obtained from Medicare Australia.

RESULTS

There was a disproportionate increase in 25(OH)D testing compared to bone density testing from 2001 to 2011, whereby 25(OH)D testing increased from 26,666 to 1.65 million p.a. and bone density testing increased from 41,453 to 66,100 p.a. Bone densitometry increased approximately 1.2 fold, whereas 25(OH)D testing increased by 55.2, 41.2 and 34.3 fold in females aged 45-54, 55-64 and 65-74 yr, respectively. This represents an increase in annual benefits from approximately $2.5-$4.1 million for bone density testing and $0.7-$40.5 million for 25(OH)D testing over the period.

CONCLUSIONS

This study demonstrates that improved detection of vitamin D deficiency is not being translated into better detection in at-risk women of the consequences of vitamin D deficiency on target organs such as bone. This failure to translate rising awareness and better detection of vitamin D deficiency into physiological outcomes is a massive missed opportunity for improved bone health and reduced fracture risk.We propose that clinical practice guidelines be introduced not only for the purpose of diagnosis and testing for vitamin D, but to include recommendations for bone health testing in at-risk individuals.

Testing for vitamin D and other trends in the clinical management of osteoporosis

SUMMARY

This descriptive paper identifies some salient trends in the Australian management of osteoporosis. Changes in pharmaceutical consumption and medical utilisation are analysed. The total national consumption of four pharmaceuticals is estimated. From 2001 to 2011, the consumption of bisphosphonates and vitamin D increased. After 2006, the management rate for osteoporosis decreased.

PURPOSE

During the first decade of the millennia, the total cost of vitamin D tests has increased significantly within many health care jurisdictions worldwide. Australia reports a 100-fold increase. Legitimately, concerns regarding the economic effectiveness of this test exist. The purpose of this paper is to identify what other salient clinical trends could affect the efficacy of this test when treating osteoporosis.

METHODS

Longitudinal data from two Australian datasets are analysed. The first are data obtained from Medicare Australia, which report pharmaceutical consumption. The second are data obtained from a national survey of general practitioners.

RESULTS

The management of osteoporosis has been characterised by a movement away from single to combination formularies. The consumption of calcium carbonate has declined, and the use of bisphosphonates has increased. While the gross consumption of risedronate increased steadily over the decade (8.4 to 186.5 kg), the consumption of alendronate declined after 2007. The consumption of vitamin D (over-the-counter and prescription) has increased from 0.58 to 2.8 kg over the decade. While prescription vitamin D comprised just 10% of the total, its consumption has undergone a 20-fold increase since 2006. Importantly, we can also report that the management of osteoporosis by Australia's general practitioners increased steadily until 2007-2008, before declining by 36%.

CONCLUSIONS

Further research is required to determine possible casual relationships that may exist between these data. Until a formal economic evaluation of vitamin D testing in this clinical setting is completed, no conclusions regarding its economic effectiveness should be drawn.

Predicting vitamin D deficiency in older Australian adults

OBJECTIVE

There has been a dramatic increase in vitamin D testing in Australia in recent years, prompting calls for targeted testing. We sought to develop a model to identify people most at risk of vitamin D deficiency.

DESIGN AND PARTICIPANTS

This is a cross-sectional study of 644 60- to 84-year-old participants, 95% of whom were Caucasian, who took part in a pilot randomized controlled trial of vitamin D supplementation.

MEASUREMENTS

Baseline 25(OH)D was measured using the Diasorin Liaison platform. Vitamin D insufficiency and deficiency were defined using 50 and 25 nmol/l as cut-points, respectively. A questionnaire was used to obtain information on demographic characteristics and lifestyle factors. We used multivariate logistic regression to predict low vitamin D and calculated the net benefit of using the model compared with 'test-all' and 'test-none' strategies.

RESULTS

The mean serum 25(OH)D was 42 (SD 14) nmol/1. Seventy-five per cent of participants were vitamin D insufficient and 10% deficient. Serum 25(OH)D was positively correlated with time outdoors, physical activity, vitamin D intake and ambient UVR, and inversely correlated with age, BMI and poor self-reported health status. These predictors explained approximately 21% of the variance in serum 25(OH)D. The area under the ROC curve predicting vitamin D deficiency was 0·82. Net benefit for the prediction model was higher than that for the 'test-all' strategy at all probability thresholds and higher than the 'test-none' strategy for probabilities up to 60%.

CONCLUSION

Our model could predict vitamin D deficiency with reasonable accuracy, but it needs to be validated in other populations before being implemented.

Newer treatments in the management of pediatric asthma

Asthma control remains a significant challenge in the pediatric age range in which ongoing loss of lung function in children with persistent asthma has been reported, despite the use of regular preventer therapy. This has important implications for observed mortality and morbidity during adulthood. Over the past decade, there has been an emergence of other treatment adjuncts, such as anti-Immunoglobulin E (IgE)-directed therapy, low dose theophylline, and the use of macrolide antibiotics, yet their exact role in asthma management remains unclear, despite omalizumab now being incorporated into several international asthma guidelines. As with many aspects of pediatric care, this is driven by a lack of appropriately designed pediatric trials. Extrapolation of data reported in adult studies may be appropriate for adolescent asthma, but is not for younger age groups, in which important pathophysiological differences exist. Novel drugs under development offer potential for benefit in the future, but to date existing data are in most cases limited to adults. Pediatric asthma also offers unique potential to prevent or modify the underlying pathophysiology. Although attempts to do so have been unsuccessful to date, advances may yet come from this approach, as our understanding about the interaction between genetics, environmental factors, and viral illness improve. This review provides an overview of the newer treatment options available for management of pediatric asthma and discusses the merits of other novel therapies in development, as we search to optimize management and improve future outcomes.

Evidence of overtesting for vitamin D in Australia: an analysis of 4.5 years of Medicare Benefits Schedule (MBS) data

OBJECTIVE

To comprehensively examine pathology test utilisation of 25-hydroxyvitamin D (25(OH)D) testing in each state of Australia to determine the cost impact and value and to add evidence to enable the development of vitamin D testing guidelines.

DESIGN

Longitudinal analysis of all 25(OH)D pathology tests in Australia.

SETTING

Primary and Tertiary Care.

MEASUREMENTS

The frequency of 25(OH)D testing between 1 April 2006 and 30 October 2010 coded for each individual by provider, state and month between 2006 and 2010. Rate of tests per 100 000 individuals and benefit for 25(OH)D, full blood count (FBC) and bone densitometry by state and quarter between 2000 and 2010.

RESULTS

4.5 million tests were performed between 1 April 2006 and 30 October 2010. 42.9% of individuals had more than one test with some individuals having up to 79 tests in that period. Of these tests, 80% were ordered by general practitioners and 20% by specialists. The rate of 25(OH)D testing increased 94-fold from 2000 to 2010. Rate varied by state whereby the most southern state represented the highest increase and northern state the lowest increase. In contrast, the rate of a universal pathology test such as FBC remained relatively stable increasing 2.5-fold. Of concern, a 0.5-fold (50%) increase in bone densitometry was seen.

CONCLUSIONS

The marked variation in the frequency of testing for vitamin D deficiency indicates that large sums of potentially unnecessary funds are being expended. The rate of 25(OH)D testing increased exponentially at an unsustainable rate. Consequences of such findings are widespread in terms of cost and effectiveness. Further research is required to determine the drivers and cost benefit of such expenditure. Our data indicate that adoption of specific guidelines may improve efficiency and effectiveness of 25(OH)D testing.

Recruitment and results of a pilot trial of vitamin D supplementation in the general population of Australia

CONTEXT

The benefits of high serum levels of 25-hydroxyvitamin D [25(OH)D] are unclear. Trials are needed to establish an appropriate evidence base.

OBJECTIVE

We plan to conduct a large-scale trial of vitamin D supplementation for the reduction of cancer incidence and overall mortality and report here the methods and results of a pilot trial established to inform its design.

DESIGN

Pilot D-Health was a randomized trial carried out in a general community setting with 12 months intervention and follow-up.

PARTICIPANTS

Participants were 60- to 84-yr-old residents of one of the four eastern Australian states who did not have any vitamin D-related disorders and who were not taking more than 400 IU supplementary vitamin D per day. A total of 644 participants were randomized, and 615 completed the study (two persons withdrew because of nonserious adverse events).

INTERVENTIONS

The interventions were monthly doses of placebo or 30,000 or 60,000 IU vitamin D(3).

MAIN OUTCOMES

The main outcomes were the recruitment rate and changes in serum 25(OH)D.

RESULTS

Ten percent of those approached were recruited. At baseline, the mean 25(OH)D was 42 nmol/liter in all three study arms. The mean change in 25(OH)D in the placebo group was 0.12 nmol/liter, compared with changes of 22 and 36 nmol/liter in the 30,000- and 60,000-IU groups, respectively.

CONCLUSIONS

The D-Health pilot has shown that a large trial is feasible in Australia and that a dose of 2000 IU/d will be needed to ensure that a large proportion of the population reaches the target serum 25(OH)D level.